Thermostat / Hygrostat Control - Lennox CLIMATIC series User Manual

AIR MANAGEMENT

THERMOSTAT / HYGROSTAT CONTROL

Function
The CLIMATIC is controlling the heating and cooling staging according to the gap between measured temperature(s) and set point(s)
and depending of the settings of the controller.
Control of the the room temperature
Description
The CLIMATIC adjusts and holds the room air temperature as close as possible to the set point, by controlling the number of compressor
stages, depending on the thermal load of the system. The controller constantly calculates the required capacity to reach the temperature
set point. This variable is called "CAPACITY FACTOR" (CF) and its value can vary from 0 to 100%.
Difference between the room
temperature and the set point
In order to anticipate, the reference point is recalculated each time the difference between air temperature and set point reaches a
minimum or a maximum.
CLIMATIC is calculating two Capacity Factor, for the room temperature one for heating mode and another one for cooling mode. It
is possible to act on the system reaction speed by modifying Integral time set points in (3228) for cooling mode and (3229) in hea-
ting mode. Increasing the integral time value will increase the time to react (slow-down).
In order to improve the management of stagging, those room temperature capacity factors will determine the blowing air tempera-
ture setting point following the rules hereunder:
In heating mode
Proportional rule between
(CF) Heat Blowing air temperature set point visible in menu (2232)
Threshold : room temperature Heating set point (2243) + offset (2254)
0%
(2252)
100%
Example
- If the Heating Capacity Factor (2228) is reaching 0% according to room temperature
heating set point (2243), measured room temperature and integral time (3229),
- then the calculated blowing air temperature set point (2232), will be equal to the
room temperature heating set point (2243) + offset for low limit threshold in heating
mode (2254).
CLIMATIC RT_UNITARY-IOM-1508-E
CF FROZEN
CF DECREASES
(removes capacity stages)
Room temperature
can change
FAST SLOW
CF INCREASES
(starts more capacity stages)
CF FROZEN
SLOW FAST
(2232)
(2252) 38°C
Room heating capacity factor
(2228)
100%
Blowing air temp set point
(2243)+-(2254) 19°C
0%
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